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A172358 Triangle t(n,k) read by rows: Padovan factorial ratios c(n)/(c(k)*c(n-k)) where c are partial products of a generalized Padovan sequence with multiplier m=2. 0
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 3, 3, 1, 1, 3, 9, 9, 3, 1, 1, 5, 15, 45, 15, 5, 1, 1, 9, 45, 135, 135, 45, 9, 1, 1, 11, 99, 495, 495, 495, 99, 11, 1, 1, 19, 209, 1881, 3135, 3135, 1881, 209, 19, 1, 1, 29, 551, 6061, 18183, 30305, 18183, 6061, 551, 29, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,12

COMMENTS

Start from the generalized Padovan sequence A159284 and its partial products c(n) = 1, 1, 1, 1, 3, 9, 45, 405, 4455, 84645, 2454705... Then t(n,k) = c(n)/(c(k)*c(n-k)).

Row sums are 1, 2, 3, 4, 11, 26, 87, 380, 1707, 10490, 79955,...

Note that rows n>=14 contain fractions. R. J. Mathar, Jul 05 2012

LINKS

Table of n, a(n) for n=0..65.

EXAMPLE

1;

1, 1;

1, 1, 1;

1, 1, 1, 1;

1, 3, 3, 3, 1;

1, 3, 9, 9, 3, 1;

1, 5, 15, 45, 15, 5, 1;

1, 9, 45, 135, 135, 45, 9, 1;

1, 11, 99, 495, 495, 495, 99, 11, 1;

1, 19, 209, 1881, 3135, 3135, 1881, 209, 19, 1;

1, 29, 551, 6061, 18183, 30305, 18183, 6061, 551, 29, 1;

MATHEMATICA

Clear[f, c, a, t];

f[0, a_] := 0; f[1, a_] := 1; f[2, a_] := 1;

f[n_, a_] := f[n, a] = f[n - 2, a] + a*f[n - 3, a];

c[n_, a_] := If[n == 0, 1, Product[f[i, a], {i, 1, n}]];

t[n_, m_, a_] := c[n, a]/(c[m, a]*c[n - m, a]);

Table[Table[Table[t[n, m, a], {m, 0, n}], {n, 0, 10}], {a, 1, 10}];

Table[Flatten[Table[Table[t[n, m, a], {m, 0, n}], {n, 0, 10}]], {a, 1, 10}]

CROSSREFS

Sequence in context: A190906 A080311 A135368 * A119560 A172364 A140366

Adjacent sequences:  A172355 A172356 A172357 * A172359 A172360 A172361

KEYWORD

nonn,tabl,less

AUTHOR

Roger L. Bagula, Feb 01 2010

STATUS

approved

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Last modified April 23 19:18 EDT 2014. Contains 240946 sequences.